Azure/Windows and Xojo Web Issue

I have moved one of our web applications from Windows 2012 R2 (a VM) where it is working perfectly fine, to Windows 2016 on Azule. I am getting the following error each time I access it in the browser.

I just spun up a Azure Windows 2012 R2 instance and I'm getting the same results. This appears to be something to do with Azure and how Xojo interacts with those VMs. Does anyone have experience with that?